A number of MPs told how they had already submitted letters of no confidence in the Prime Minister to Sir Graham Brady, chairman of the 1922 Committee, and others discussed plans to follow suit.

But leading members of the group have since dismissed the idea they are plotting the PM’s demise.

ERG chairman Jacob Rees Mogg, who was not present at last night’s meeting, insisted he was seeking a change to the Government’s Brexit policy rather than a change in leadership.

“I have long said, and repeated again and again, that the policy needs to be changed but I am supporting the person,” he said.

Tory Brexiteers are reportedly plotting to oust Theresa May (Getty)

Steve Baker, a leading figure in ERG, insisted this morning that the group was not pushing for the PM to be replaced, saying that anyone calling for her to be ousted was ‘speaking for themselves’.

MP Michael Fabricant, who attended the meeting, said that reports of a plot to unseat Mrs May were ‘greatly exaggerated’.

I attended the ERG last night.Reports of @theresa_may's demise are greatly exaggerated.Of the 40-50 there, only 5-6 people discussed letters to the Chairman of the 1922 and they wrote ages ago.The rest of us sat in uncomfortable silence.Though most are unhappy with #Chequers

What happens if enough letters of no confidence are handed in?

Mrs May would need the support of more than 50% of Conservative MPs – currently 159 – in the confidence vote to stay in office. Candidates for the leadership must be nominated by two Conservative MPs. If only one candidate comes forward, he or she becomes leader. If a number of would-be leaders are nominated, the list is whittled down to a shortlist of two by MPs. The final two then go to a postal ballot of all party members, with the position of leader, and Prime Minister, going to the victor.

What would happen if Mrs May wins?

She can stay on as leader, however a narrow victory could seriously undermine her authority and may lead her to question whether it was right to carry on.

What if she loses?

If the PM lost the vote she would not be able to stand in the subsequent leadership contest, meaning a new leader – and Prime Minister – would be elected.